Method of sulfidizing metals.



icnrrnn STATES rarest @FEECE. I I

HENRY B. HOVLAND, 0F DULUTH, MINNESOTA.

METHOD or suLmmznve METALS.

No Drawing.

The present invention has for its objectto provide an improved method ofsulfidizing the metallic constituents of ores and other metalliferousmaterials.

Metals may be extracted from ores'or other metal-bearing materials byfirst bringing the metal into solution by means of a solvent. and thentreating with a sulfidizing agent to sulfidize and precipitate the metalas artificial. metal sulfid which may be separated by the well-knownflotation process. I

In a process conducted on a commercial scale,,it is of importance thatan economical sulfidizing agent be employed and the present inventionaims to provide an economical sulfidizing method.

.Brietly stated, the improved method consists in bringing togethercalcium sulfid, ferric sulfate and the solution of the metal to besulfidized. For the sake of conven= ience, the method will be describedas applied to the recovery of copper from its ores, but it will beunderstood that the in.

vention is not limited to the treatment of copper ores or even ores ingeneral, but may.

be applied to the sulfidizing of the metals of all metalliferousmaterials.

So far as the present invention is concerned, it is immaterial how themetal to be sulfidized is first brought into solution. One method is togrind oxidized ore to a suitable fineness and to'treat the ground orewith sulfuric acid until the soluble contents of the ore is in the formof sulfate. .Vhen -copper ore is treated, the addition of the sulfuricacid forms copper sulfate. Calcium sulfid and ferric sulfate are thenadded in sulficient amounts to the pulp and copperbearing liquor toprecipitate the copper" present in the form of copper sulfid. As

soon as the calcium sulfid and ferric sulfate are added to the copperliquor. a reaction takes place and the copper is sulfidized. While thepresence of free acid in the solu- Specification of Letters Patent.

Patented Nov. *9, H315.

Application filed July 16, 1915. Serial No. 40,179.

tion is not necessary, it has been found advantageousto provide someacid in order to utilize to the fullest extent, the sulfur contained inthe calcium sulfidand the ferric sulfate.

If calcium sulfid is added to the metal solution alone, metal sulfidswill not be precipitated as the desired reaction will not take place.Vhen ferric sulfate and calcium sulfid however, are used, the ferricsulfate facilitates theconveyance of the sulfur to the metal to besulfidized.

This method of sulfidizing is economical for the reason that calciumsulfid may be prepared at low cost in any locality Where there is limeor limestone and sulfurous acid, free sulfur or metal sulfids available.For instance, lime or limestone'and a metal sulfid may be mixed andheated to form a calcine, which has been found to be a satisfactorycalcium sulfid containing substance for the present purpose as it isimmaterial whether the calcium sulfid is pure or mixed with othersubstances. Or, the calcium sulfid may be prepared in localities wherenative gypsum occurs, especially in. localities Where the gypsum isfound interbedded with coal measures affording the reducing agent forreducing the calcium sulfate to calcium sulfid, which lat-. ter is thenquite pure and serviceable as a sulfidizing agent. The ferric sulfatemay be prepared in ordinary roasting operations in any localityWherethre is available iron sulfid or iron oXids and sulfur-yieldingcompounds.

As above stated, the invention is not limited to the treatment of copperores, as the metal of any metalliferous material may be brought intosolution and then precipitated by means of thecalcium sulfid and ferricsulfate, in the form of a sulfid of the metal to be recovered.

hat I claim is 1. The method of treating metalliferous materials whichconsists in bringing the '3; The method of sulfidizing metal which iconsists in bringing together a solution of 5. Theimethodof sulfidizingmetal-which the metal to be srllficlized, calcium sulfid and consists intreating a solution of the metal ferric sulfate. to. be sulfidizecl Withferric sulfate in the 10 4c. The method of precipitating the metalpresence of calcium sulfid. 5 -from a metal-containing solutionWhich'con In testimony whereof I affiXmy signature. si's'tsin treatingthes'olution with calcium sulfid, ferric sulfate and an acid. I HENRY B.HOVLAND.

0o1iies-of this patent may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington} D. O.

